Connection String using DSN

This question requires experience with Visual Studio .NET 2005. I created an n-tiered application and in the Data Access Layer I used a direct connection to the Database by specifying the server, username, password, etc in the connection string. Now I want to change this so that the application connects to the Database through a DSN defined on the local machine that connects to the server. So I went ahead and changed the connection settings to point to a dsn. The connectio string looks like this after the change: Dsn=dsnname But I get an error when the connection is initialized at run time telling me that 'dsn' is not a recognized string in the connection string. Please remember that in both cases I did not generate the connection string manually, VS did it for me. Any help will be appreciated.